Lava Lakes: The Exposed Guts of Volcanoes

Most volcanoes have a deep inner chamber of molten rocks, but this chamber is typically capped shut by cooled, solid rock. But sometimes the magma chamber is exposed at the top of the volcano in a giant caldera of rolling, bubbling and spluttering lava. This happens when an active volcano continuously pushes new molten rocks up the vent to form a pool inside the caldera, while solidified lava sinks back into the depth to be re-melted. Volcanologists often describe lava lakes as “windows into the heart of volcanoes.” “Persistant lava lakes are very rare, and require a delicate equilibrium between heat supply and heat loss,” says VolcanoDiscovery.com . “Heat supply is provided by rising magmatic gasses from the magma chamber through a liquid-filled conduit, and is counterbalanced by intense heat lost at the surface of the lava lake.” The lava lake of Mount Nyiragongo. Photo credit: Olivier Grunewald/Boston.com There are only a handful of persistent lava lakes in the world. The most famous lava lake is the one on Mount Nyiragongo , in the Democratic Republic of the Congo. The lake is about 1.2 km across, the largest in existence, and is about 600 meters deep. It is not known when the lava lake formed, but the volcano has been erupting since 1882. The volcano is infamous for its extremely fluid lava that may race downhill at up to 100 km/hr when the lava lake drains. On 10 January 1977, the crater walls fractured, and the lava lake drained in less than an hour overwhelming villages and killing at least 70 people. Another major eruption occurred in 2002. Fortunately, warnings had been given and 400,000 people were evacuated. Still 147 people died from asphyxiation and buildings collapsing. The lava lake of Mount Nyiragongo. Photo credit: Cai Tjeenk Willink/Wikimedia The lava lake of Mount Nyiragongo. Photo credit: Olivier Grunewald/Boston.com The lava lake of Mount Nyiragongo.